Compositions and processes for the treatment of fourdrinier wire cloths of papermaking machines



Unite States atent 3,140,974 COMPOSITIONS AND PROCESSES FOR THETREATMENT OF FOURDIER WEE CLQTHS F PAPERMAG MACHINES John D. Pera, FredW. Baths, and Robert F. Drescher, Memphis, Tenn., assignors to BushmanLaboratories, Inc, Memphis, Tenn, a corporation of Tennessee No Drawing.Filed July 3, 1961, Ser. No. 121,383 12 Claims. (Cl. 162-199) Thepresent invention relates to compositions and processes for thetreatment of Fourdrinier wire cloths composed of strands ofcopper-containing alloys that are used in papermaking machines,particularly to processes of treating such wire cloths to provideprotection from mechanical wear, to which the wires of such machines arenormally subjected, and thereby increase the useful life of such wirecloths.

Studies which have been made to determine factors that influence thelife of Fourdrinier wire cloths on papermaking machines reveal that thetwo main factors that influence the useful life of such cloths areactual damage to the Wire and mechanical wear; corrosion, as such, isgenerally regarded as a factor of lesser importance than these two otherfactors.

The process of making paper consists of three fundamental operations,namely, hydration of cellulosic fibers with water to form a slurry ofpulp and water, the deposition of the fibers of the pulp and formationof a sheet of paper therefrom on a Fourdrinier wire cloth and, finaL ly,dehydration of the paper sheet thus formed. In such processes, acellulosic pulp and water slurry combined with other papermakingingredients, which is called the furnish, is added to the headbox of aFourdrinier machine to provide a continuous supply of the furnish to themachine. The headbox functions in such a way as to provide a homogeneousdispersion of the furnish flowing continuously in a relativelynon-turbulent manner through the slice of the headbox (an openingextending across the entire width) onto a Fourdrinier wire cloth. TheFourdrinier Wire cloth carries the furnish from the breast roll adjacentthe headbox forward to the couch roll, at which point the newly formedpaper web or sheet is transferred to other sections of the machine inwhich water is gradually removed from the formed paper sheet. Theendless Fourdrinier wire cloth then returns to the breast roll where itagain receives additional amounts of furnish from the headbox.

The function of the Fourdrinier wire cloth is to support the mass offurnish until suflicient water has been removed from the wet paper sheetdeposited thereon, so that the sheet has .suiiicient strength to supportits own weight without breaking. Additional devices that are used toassist in the removal of water from the newly formed sheet are theforming board, table rolls, suction boxes, and suction rolls. TheFourdrinier wire used commonly includes a warp formed of strands ofwires of a Phosphor bronze which is a copper-tin alloy, containing arelatively small amount of tin, such as 7 to 8 percent, with the balancecopper, while the shute strands are composed of red brass, which usuallycontains zinc in an amount of approximately to percent, with the balancecopper.

The Fourdrinier wire cloth is supported by and rotates around the breastroll at one end and the couch roll at the other. Between these rollsadditional support is obtained by a forming board, a series of tablerolls and a series of suction boxes. The Fourdrinier wire cloth isdriven by the couch roll and the supplementary drive rolls. Itsalignment on the machine is maintained by one or more guide rolls andproper tension of the cloth is maintained by one or more stretch rolls.

Because of the vital function served by the Fourdrinier wire cloth inthe papermaking operation, and because it is extremely susceptible tomechanical stresses, abrasion, and other deleterious influences, thewire cloth must be protected from lumps of furnish that may accumulatebetween the various rolls and the wire cloth and distend the wire cloth.The means most frequently adopted for this purpose is that of providingwater showers located at various positions relative to the wire cloth towash and remove any lumps of furnish that may have collected upon thewire cloth and the wire return rolls.

The care used in the installation of wire cloths on papermaking machinesis an important factor influencing the useful life of all such wirecloths. In general, longer and finer mesh wires are damaged more easilythan shorter and coarser mesh wires. Damage that can result fromcareless installation of the wire cloths on papermaking machinesincludes creasing, as well as damage during operation from downward andupward furnish jams, edge cracks, etc. As suggested by the nature ofthese problems, the relative importance of damage versus mechanical wearvaries from machine to machine. When adequate steps are taken to reducedamage to a minimum, mechanical wear then becomes the principal factorlimiting wire life.

The most important factors which contribute to mechanical wear of wirecloths are the drag load exerted by the suction boxes, speed of the wirecloth, and the quantity of abrasive grit present in the furnish as itflows from the headbox on to the wire cloth. Wear occurs primarily onthe underside of the wire cloth. It results from pulling the wire clothat a relatively high rate of speed over the surfaces of the stationarysuction boxes to which a vacuum has been applied to facilitate theremoval of water from the sheet of paper formed on the surface of thewire. When the surfaces of the suction boxes have grit or other abrasiveparticles embedded in them, the rate of mechanical wear is furtherincreased. In order to reduce mechanical wear, use of materials otherthan wood for suction-box covers, reduction of the vacuum applied tosuction boxes, and a more complete removal of grit from the paperfurnish have been suggested. However, progress on the reduction ofmechanical wear of wire cloths has been limited to investigation offactors such as these. The increasing speeds which are gradually beingadopted on papermaking machines have made it necessary to consider othermeans for increasing the useful ife of Fourdrinier wire cloths in termsof days of operation.

One of the objects of the present invention is to provide compositionswhich when applied to such wire cloths act as anti-wear orwear-inhibiting agents and thereby extend the useful life of such clothson papermaking machines. Another object of the present invention is toprovide processes for the treatment of copper-containing alloyFourdrinier wire cloths, which will reduce the mechanical wear of suchwires on the papermaking machine. Other objects and advantages of thisinven- -on the strands by the treatment.

tion, some of which are referred to hereinafter, will be obvious tothose skilled in the art to which it pertains.

It has now been discovered that mechanical wear of copper-containingalloy Fourdrinier wire cloths can be reduced by applying directly to thewire cloths or adding to the aqueous fluids with which these wire clothscome into contact, compositions containing a mixture of 2-aminoethanoland an alkali-metal salt of Z-mercaptobenzothiazole. Although neither ofthese substances when added alone has any significant effect onmechanical wear of such wire cloths, combinations of the two in therange of ratios specified herein reduce the mechanical wear and increasethe useful life of such wire cloths. Although mixtures of thesesubstances appear to adhere to or deposit a film upon the individualwire strands of the cloths, the exact mechanism of this unusual actionhas not as yet been ascertained. However, these substances appear to actas antiwear or wear-inhibiting agents. The film thus deposited not onlyprovides incidental corrosion inhibition, but also increases theresistance of the wire to mechanical wear, erosion, or other effects, asa consequence of which the life of such wires is extended beyond theirtheretofore useful life.

Mixtures of Z-aminoethanol, which is also commonly known asmonoethanolamine and simply as ethanolamine, and alkali-metal salts ofZ-mercaptobenzothiazole which 'were found useful for the purposesspecified herein are those within the range of ratios betweenapproximately 35 and approximately 60 parts by weight of 2-aminoethanolto between approximately 65 and approximately 40 parts by weight of thealkali-metal salt of 2-mercaptobenzothiazole based on itsZ-mercaptobenzothiazole equivalent. A preferred composition is anaqueous solution containing equal parts by weight of Z-aminoethanol andZ-mercaptobenzothiazole as its alkali-metal salt, such as is illustratedin Example 3 hereinafter.

When a Phosphor-bronze wire cloth is immersed in an aqueous solutioncontaining an alkali-metal salt of 2-mercaptobenzothiazole andZ-aminoethanol in ratios within the specified range, and then washedwith water, the strands of the wire cloth become coated with a film ofthe mixture. This film remains even after removing the water. Wire clothwetted or coated with the film in this manner is more resistant tostaining by sulfide ion and corrosion than untreated wide cloths. Whenthe wire cloth is treated with a mixture containing less 2-aminoethanolor less Z-mercaptobenzothiazole than the ratios specified, a lesseramount of film remains on the wire cloth and the wire cloth is itselfmore susceptible to staining by sulfide ion and to corrosion. In Example1 hereinafter, in which composition B containing 2-aminoethanol andsodium Z-mercaptobenzothiazole in ratios outside the specified range wasused, the useful life of the wire cloth treated therewith was less thanthat of the wire cloth treated with composition A, which containedamounts of these compounds within the specified range of ratios.

Elemental analysis of strands of copper-containing alloy Fourdrinierwire cloths treated in accordance with the processes of this inventionreveal the presence of nitrogen and sulfur. This confirms that a film isdefinitely formed This film is not readily removable by washing withwater and appears to be firmly held.

In the examples which follow a preferred process and composition forpracticing the present invention are included.

EXAMPLE 1 Addition of Composition A to the Furnish of a PapermakingMachine The papermaking machine referred to in this example is one thatis used to produce newsprint from a pulp consisting of a mixture ofgroundwood and kraft southern pine pulps. The machine produces a grossheadbox tonnage of 270 tons per day. The headbox consistency is 0.7percent (percentage of parts by Weight of pulp to parts by weight ofwater). The temperature of the furnish is F. and its pH is 5.0. Theendless Fourdrinier wire cloth on this machine during operation travelsat a speed of 1,820 feet per minute. This Fourdrinier wire cloth isformed of Phosphor bronze and red brass, having a mesh of 60/46 strandsper inch, a width of 213.5 inches and a length of 116 feet 5 inches.These mesh numbers refer to strands per linear inch; the first numberrefers to Warp strands that run lengthwise, that is, in the machinedirection; the second refers to shute strands, running in the oppositedirection, namely, crosswise to the machine direction.

An aqueous solution, referred to herein as composition A, which containsthe following substances in percentages by weight:

Percent by weight Disodium cyanodithioimidocarbonate 9.4 Ethylenediamine3.5 Potassium N-methyldithiocarbamate 1&9 Sodium Z-mercaptobenzothiazole13.8 Z-aminoethanol 12.2

was continuously added to the furnish at the reject screen of themachine at the rate of 0.46 pound per ton of paper produced. This amountof composition A provided a concentration 1.5 ppm. throughout the systemcontinuously. The mixture of composition A commingled with the furnishthen flowed from the headbox onto the endless Fourdrinier wire clothtraveling at high speed. Composition A came into intimate contact withthe wire cloth during the process of removing water from the sheetformed on the wire cloth.

In the table which follows hereinafter is summarized .the performance ofwires on this papermaking machine, some of which were subjected totreatment with the foregoing composition A, and one of which was treatedwith composition B, a similar chemical composition designed to provideadequate slime control and to reduce the darkening of Fourdrinier wires,which consists of an aqueous solution containing the followingsubstances in percentages by weight:

Percent by weight Disodium cyanodithioimidocarbonate 10.0Ethylenediamine 3.7 Potassium N-methyldithiocarbamate 13.7 SodiumZ-mercaptobenzothiazole 14.7 Z-aminoethanol 6.5

Composition B, which contains the same components as composition A, butcontains a smaller ratio of Z-aminoethanol to sodiumZ-mercaptobenzothiazole, had no appreciable effect on the useful life ofthe Fourdrinier wires. The wire that had been subjected to treatmentwith composition B is included in the table only to provide a basis ofcomparison.

Each of the wires included in the performance data tabulated hereinafterwere kept in continuous use on the papermaking machine until they wereno longer usable. The number of days specified in the third column ofthis table represents the maximum period of useful performance or lifewhich each wire provided on this machine before replacement wasnecessary.

As shown in the foregoing table, composition A increased the useful lifeof the wire cloths on this machine by as much as 32 percent.

EXAMPLE 2 Application of Composition A to the Wire Cloth Through theWire Showers of a Papermaking Machine The papermaking machine referredto in this example is used to produce light, medium, and heavy-weightgrades of kraft paper, unbleached kraft liner board, also unbleachedkraft pulp. Its normal production is 300 tons per day. The headboxconsistency of the furnish varies from 0.2 to 0.5 percent. Thetemperature of the furnish in the headbox is approximately 110 F. andits pH is usually between 5.0 and 6.0, but when the machine is used toproduce unbleached kraft pulp, the pH may be as high as 8.0. The endlessFourdrinier wire cloth on this machine travels at speeds between 1,000and 1,750 feet per minute, although most of the time the machine isoperated at a speed between 1,500 and 1,600 feet per minute.

The wire cloths used on this machine are 138 feet 11 inches long and 264inches wide. Only one out of every four wire cloths used on this machinehas a mesh of 60/48, the machine being more frequently used with clothshaving a mesh of 60/49. The type of Wires used are exemplified by thefollowing composition: shute wire, alloy containing 85 percent copperand 15 percent zinc; warp wire, alloy containing 92 percent copper and 8percent tin.

Composition A, whose composition is specified in Example 1 hereinbefore,was fed at the rate of 1.2 pounds per ton of paper produced into thewater flowing through six wire showers. Each of these wire showers waslocated inside the endless wire cloth and between the breast and couchrolls, extended across the entire width of the wire, and dischargedstreams through nozzles that impinged onto the underside of the wirecloth as it returns from the couch to the breast roll. Water having a pHof 7.0 and a temperature of 110 F. was used in these six showers at therate of 1,000 gallons per minute.

In this example, composition A was first injected into the water flowingthrough all six showers in such amounts that the water impinging on thewires contained ppm. of composition A. Six consecutive wire cloths(numbered 17 to 22 in the table hereinafter) were treated continuouslyin this manner during the operation of the machine. Thereafter, inconnection with two wire cloths (numbered 23 and 24) composition A wasadded only to the water supplying the last three showers, those nearestthe breast roll, in an amount such as to provide 60 ppm. of compositionA in the shower water impinging on the wire cloth.

The results reported in the table which follows represent the number oflinear feet which each wire cloth travelled on the machine duringpapermaking operations before it was replaced. Wire cloths numbered 17to 24 had been treated by addition of composition A to the shower waterin the manner described hereinbefore, while wire cloths numbered 1 to 16had been treated with composition C, which was an aqueous solutioncontaining the following ingredients in the specified percentages byweight:

Percent by weight Disodium cyanodithioimidocarbonate 12.7Ethylenediamine 4.8 Potassium N-methyldithiocarbamate 17.5

The additions of composition C were made at a rate of 4 ppm. for aperiod of 6 hours daily to the papermaking machine at the fan pump fromwhich the furnish flowed onto the Fourdrinier wire cloth through theheadbox. The average footage travelled by each of the 16 wires treatedwith composition C was 17,369,176 feet. When Total foot- Wire Cloth N0.Treatment age run 1 Composition 0 23, 497, 710

EXAMPLE 3 A pplidation of Composition D Through the Wire Showers 0 aPapermaking Machine The papermaking machine referred to in this exampleis the same as that referred to in Example 2 hereinbefore, and wires ofsimilar composition were used on this machine.

Composition D which was used in this example is an aqueous solutioncontaining the following ingredients in the specified percentages byweight:

Percent by weight Sodium Z-mercaptobenzothiazole (based on its 2-mercaptobenzothiazole equivalent) 26.0 Z-aminoethanol 26.0

Composition D was fed into the water supplying the two wire showersnearest the breast roll at a rate of 1.04 pounds of composition D perton of paper production, which corresponds to a concentration of 78 ppm.of composition D (or approximately 40 ppm. of 2-aminoethanol andZ-mercaptobenzothiazole) in the shower water.

One Fourdrinier wire cloth that was thus treated had a useful life of atleast 31,000,000 feet, which represents an increase of at least 78.5percent over 17,369,176 feet, which is the average footage of the wiresreferred to in Example 2 that had been treated with composition C.

A second similar Fourdrinier wire cloth treated in the same manner withcomposition D had a useful life of 39,254,000 feet, which represents anincrease of 126 percent, even though this wire had been damaged bycrimping when it was installed on the machine.

Composition D referred to in Example 3 is a fluid composition thatrepresents a convenient form in which the mixture of alkali-metal saltof Z-mercaptobenzothiazole and Z-aminoethanol may be dispensed and usedin such papermaking operations. The application of the mixture directlyto the wire cloth through the wire showers is also regarded as apreferred method of treating the wir in accordance with the processes ofthis invention.

EXAMPLE 4 Composition E A composition was prepared by mixing 41.4 gramsof an aqueous solution containing 10.1 grams of disodium fluidscirculating in the machine. vis applied directly as an aqueous solutionto the wire be- -cyanodithioimidocarbonate with 26.4 grams of an aqueoussolution containing 13.8 grams of potassium N-methyldithiocarbamate and3.7 grams of ethylenediarnine. To the resulting solution were added 13.0grams of Z-arninoethanol, 13.0 grams of Z-mercaptobenzothiazole, and 2.4"grams of sodium hydroxide. The clear, orange-colored solution thusobtained may be used in paper machine systems in the same mannersasdescribed in the other examples herein.

EXAMPLE f f' ff Application of Composition A to the Wire iCloth Throughthe Wire Showers of a Papcrmaking Machine The papermaking machinereferred to inthis. example is used to produce 9-point corrugatingmedium at a normal production rate of 220 tons per day. The headboxconsistency of the furnish is 1.0 percent. The temperature of thefurnish in the headbox is approximately 120 F. and its pH is usually8.0. The endless Fourdrinier wire cloth on this machine travels at aspeed of 845 feet per minute.

The wire cloths used on the machine are 110 feet 9 inches long and 190inches wide and have a mesh of 56/34. Both the warp and shute wires werecomposed of all bronze alloy.

Composition A, whose composition is specified in Example 1 hereinbefore,was added to the wire pit, the fluids from which are reused in thepreparation of the furnish, in a slug dose of 25 pounds when the wirewas first installed on the machine and fed continuously thereafter atthe rate of 0.5 pound per ton of paper produced into the water flowingthrough a single wire shower. This Wire shower was located inside theendless wire cloth between the breast and couch rolls and extendedacross the entire width of the wire. The stream from the showerdischarged through nozzles that impinged onto the underside of the wirecloth as it passed a return roll on its return from the couch to thebreast roll. The water used in the shower was untreated lake waterhaving a pH of 5.5 to 6.0 and which had no buffering capacity, so thatthe solution of composition A in this water produced an alkaline pH inthe shower water. The shower delivered 250 gallons per minute at apressure of 110 psi. and the concentration of composition A was thus 37ppm. in the shower water. 7

Composition C, whose composition is specified in Ex- It was fed at therate of 0.5 pound per ton at the wire pit for a period of '6 hours eachday and thus was present at a concentration of 2.5 p.p.m. based on theweight of the aqueous fluids in the system.

The average useful life of wire cloths thus treated with composition Cwas 14 days while the useful life of the wire thus treated withcomposition A was 26 days. The useful life of the wire cloth wasincreased by 86 percent when the treatment with composition C wassubstituted for the treatment with composition A.

The foregoing examples comprise preferred embodiments of the inventionwhich were selected merely for purposes of illustration. The potassiumand other alkalimetal salts of Z-mercaptobenzothiazole may be used inplace of the sodium salt in equivalent amounts. The 2- aminoethanol andalkali-metal salt of 2-mercaptobenzothiazole may be added separately orin admixture with each other to any of the units of a papermakingmachine provided with copper-alloy Fourdrinier wire cloth and in amountsso as to provide a concentration on the Wire sufflcient to form anadherent film on the individual strands. This normally will be an amountin excess of 0.5 ppm. by weight of the mixture based on the weight ofaqueous Preferably the mixture fore it is installed on the machine. Thefilm thus deposited is then maintained and replenished by furtheradditions of the composition to the wire shower water or to a specialshower provided for direct application to the wire duringoperation ofthe machine. The concentration of the mixture which would preferably beused in the special shower would be at least 40 parts per million of themixture in the shower water and need not exceed 5.0 percent generallyspeaking.

Compositions A, B, C, and E, each of which contain a mixture of disodiumcyanodithioimidocarbonate, ethylenediamine, and potassiumN-methyldithiocarbamate, are useful components of compositions for thepurpose of controlling slime and iron bacteria in paper-makingoperations, as described in US. Patent No. 2,929,758. The use ofcompositions containing these chemical compounds for this purpose,however, may in some instances produce darkening of the Fourdrinier wirecloth by formation of a black copper sulfide deposit or film on thesurface of the strands of the Wires. In extreme cases, such films ofcopper sulfide may partially plug or clog the openings of theFourdrinier wire cloth, thereby reducing the rate at which water drainstherethrough. This Wire darkening can be inhibited by the addition tosuch compositions of Z-aminoethanol and an alkali-metal salt ofZ-mercaptobenzothiazole. However, when Z-aminoethanol and analkali-metal salt of Z-mercaptobenzothiazole are added to suchcompositions in amounts conforming to the ratios specified herein, notonly will the darkening be inhibited, but the useful life of such wireswill be extended as described herein. The additional components presentin such compositions appear not to affect or decrease the inherent powerof the mixture of 2-aminoethanol and alkali-meta1 salt of2-rnercaptobenzothiazole to extend the useful life of such Fourdrinierwire cloths. Moreover, the microbiocidal activity of such additionalcomponents appears not to be adversely affected 'by admixture with theZ-aminoethanol and alkali-metal salt of Z-mercaptobenzothiazole.

In addition to the foregoing compositions, useful compositions thatcontain some but not all of the foregoing ingredients in addition to2-aminoethanol and alkali-metal salt of Z-mercaptobenzothiazole in theamounts specified herein are included within the scope of thisinvention.

'These compositions may contain as additional components only awater-soluble salt of cyanodithioimidocarbonic acid, or a water-solublesalt of an N-monoalkyl-substituted dithiocarbamic acid, the alkylradicals of which have fewer than four carbon atoms, or a mixture of thewatersoluble salt of cyanodithioimidocarbonic acid and ethylenediamineor other diaminoalkane having not more than six carbon atoms in whichthe amino substituent radicals are on adjacent carbon atoms in an amountconforming to a molecular ratio not substantially in excess of 1.5

moles of the diaminoalkane to each mole of the cyanodi-.thioimidocarbonate, for example, such compositions as tion that areuseful for the purposes specified herein may consequently be regarded asaqueous solutions containing the following components in amounts fallingwithin the range of percentages by weight specified for each in thefollowing table. The last three components are, as stated hereinbefore,desirable components but all three or one or more of them may be omittedas indicated by the intended use of the particular composition.

acid 8-25 Ethylenediamine or other diaminoalkane as specified 3-10Water-soluble salt of N-methyldithiocarbamic acid or otherN-monoalkyl-substituted dithiocarbamate as specified 12-40 Inasmuch asthe foregoing specification comprises preferred embodiments of theinvention, which were selected for purposes of illustration, it is to beunderstood that the invention is not restricted to such embodiments, andthat modifications, variations, and alternatives, including such as aredescribed or suggested hereinbefore, or which are required to adapt theprocesses to particular papennaking machines or operations, may be madewithout departing from the invention, whose scope is limited solely bythe appended claims.

What is claimed is:

1. A composition comprising 2-aminoethanol and an alkali-metal salt ofZ-mercaptobenzothiazole in amounts conforming to ratios between and 60parts by weight of Z-aminoethanol to between 65 and parts by weight(based on its Z-mercaptobenzothiazole equivalent) of the alkali-metalsalt of 2-mercaptobenzothiazole.

2. A composition of the group consisting of (1) compositions consistingessentially of aqueous solutions of 2- aminoethanol and alkali-metalsalts of Z-mercaptobenzothiazole in amounts conforming to ratios between35 and 60 parts by weight of Z-aminoethanol to between 65 and 40 partsby weight (based on its Z-mercaptobenzothiazole equivalent) of thealkali-metal salt of 2-niercaptobenzothiazole, and (2) compositionsconsisting essentially of aqueous solutions of Z-aminoethanol andalkali-metal salts of Z-mercaptobenzothiazole in amounts conforming tothose specified in the foregoing composition (1), together with acomponent of the group consisting of (a) watersoluble salts ofcyanodithioimidocarbonic acid, (b) watersoluble salts ofcyanodithioimidocarbonic acid and a dlaminoalkane having not more thansix carbon atoms in which the amino substituent radicals are on adjacentcarbon atoms, the molecular ratio of the diaminoalkane tocyanodithioimidocarbonate in the composition being not more than 1.5,(c) water-soluble salts of cyanodithioimidocarbonic acid, adiaminoalkane having not more than six carbon atoms in which the aminosubstituent radicals are on adjacent carbon atoms, the molecular ratioof the diaminoalkane to cyanodithioimidocarbonate in the compositionbeing not more than 1.5, and water-soluble salts ofN-monoalkyl-substituted dithiocarbamic acids, the alkyl radicals ofwhich have fewer than four carbon atoms, and (d) water-soluble salts ofN-monoalkyl-substituted dithiocarbamic acids, the alkyl radicals ofwhich have fewer than four carbon atoms.

3. A composition consisting essentially of an aqueous solutioncontaining 2-aminoethanol and an alkali-metal salt of2-mercaptobenzothiazole in amounts conforming to ratios between 35 and60 parts by weight of 2-aminoethanol to between 65 and 40 parts byweight (based on its 2-mercaptobenzothiazole equivalent) of thealkalimetal salt of 2-mercaptobenzothiazole.

4. A composition consisting essentially of an aqueous solutioncontaining equal parts by weight of 2-amino- 10 ethanol and analkali-metal salt of 2-me1captobenzothiazole (based on itsZ-mercaptobenzothiazole equivalent).

5. A composition consisting essentially of an aqueous solution of2-arninoethanol, an alkali-metal salt of 2-mercaptobenzothiazole, awater-soluble salt of cyanodithioimidocarbonic acid, and a diaminoalkanehaving not more than six carbon atoms in which the amino substituentradicals are on adjacent carbon atoms, the molecular ratio of thediaminoal-kane to the cyanodithioimidocarbonate in the composition beingnot more than 1.5 and the amounts of the 2-arninoethanol andalkali-metal salt of Z-mercaptobenzothiazole conforming to a ratiobetween 35 and 60 parts by weight to between 65 and 40 parts by weight(based on its 2-mercaptobenzothiazole equivalent) of the alkali-metalsalt of Z-mercaptobenzothiazole.

6. A composition consisting essentially of an aqueous solution of2-aminoethanol, an alkali-metal salt of 2-mercaptobenzothiazole, awater-soluble salt of cyanodithio imidocarbonic acid, a diaminoalkanehaving not more than six carbon atoms in which the amino substituentradicals are on adjacent carbon atoms, and a water-soluble salt of anN-monoalkyl-substituted ditniocarbamic acid, the alkyl radical of whichhas fewer than four carbon atoms, the molecular ratio of thediaminoalkane to the cyanodithioimidocarbonate in the composition beingnot more than 1.5, and the amounts of the 2-aminoethanol and alkalimetalsalt of Z-mercaptobenzothiazole conforming to a ratio between 35 and 60parts by weight to between 65 and 40 parts by weight (based on itsZ-mercaptobenzothiazole equivalent) of the alkali-metal salt ofZ-mercaptobenzothiazole.

7. A composition consisting essentially of an aqueous solutioncontaining the following substances in proportions proximating thefollowing percentages by weight: disodium cyanodithioimidocarbonate 9.4,ethylenediamine 3.5, potassium N-methyldithiocarbamate 12.9, sodium2-mercaptobenzothiazole 13.8, and 2-aminoethanol 12.2.

8. A composition consisting essentially of an aqueous solutioncontaining the following substances in proportions proximating thefollowing percentages by weight: disodium cyanodithioimidocarbonate10.1, ethylenediamine 3.7, potassium N-methyldithiocarbamate 13.8,sodiun 2-mercaptobenzothiazole 14.7, and 2-aminoethanol 13.

9. In a process for the production of paper in which an aqueous fluidcontaining cellulosic pulp and other papermaking ingredients iscirculated in contact with a Fourdrinier wire cloth composed of strandsof coppercontaining alloys that are normally subject to mechanical wear,the method of increasing the useful life of such wire which comprisesadding to aqueous fluids with which the said wire cloth comes intocontact, 2-aminoethanol and an alkali-metal salt of2-mercaptobenzothiazole in amounts conforming to ratios between 35 and60 parts by weight of Z-aminoethanol to between 65 and 40 parts byweight (based on its Z-mercaptobenzothiazole equivalent) of analkali-metal salt of Z-mercaptobenzothiazole and at such rate as toprovide a concentration of the said two compounds of at least 0.5 partper million by weight of the aqueous fluids in the ratio set forth abovein said system.

10. A process comprising adding to the aqueous fluids of a papermakingmachine system that includes a Fourdrmier wire cloth the strands ofwhich are composed of copper-containing alloys a mixture containing2-amino ethanol and an alkali-metal salt of 2mercaptobenzothiazole inamounts conforming to ratios between 35 and 60 parts by weight ofZ-aminoethanol to between 65 and 40 parts by weight (based on itsZ-mercaptobenzothiazole equivalent) of the alkali-metal salt ofZ-mercaptobenzothiazole, at a rate such as to provide a concentration ofthe components of the mixture of at least 0.5 part per million by weightof the aqueous fluids in the ratio set forth above in the said system.

11. A process for the treatment of a Fourdrinier Wire cloth composed ofcopper-containing alloy strands which comprises contacting the saidcloth with an aqueous solution containing at least 40 parts per millionby weight of a mixture of Z-arninoethanol and an alkali-metal salt ofZ-mercaptobenzothiazole in amounts conforming to ratios between 35 and60 parts by Weight of Z-aminoethanol to between 65 and 40 parts byweight (based on its Z-mercaptobenzothiazole equivalent) of thealkalimetal salt of Z-mercaptobenzothiazole.

12. A Fourdrinier wire cloth formed of strands of copper-containingalloy wires carrying a film containing Z-mercaptobenzothiazole andZ-aminoethanol.

References Cited in the file of this patent UNITED STATES PATENTSUbbelohcle Oct. 15, Brooks Ian. 15, Bustin Dec. 25, Hatch June 21, AndelOct. 3, Hopkins Nov. 14,

OTHER REFERENCES Some Corrosion Inhibitors, from Corrosion, vol. 11, No.4, pages 65, 66 and 67, April 1955, 212.7.

12. A FOURDRINIER WIRE CLOTH FORMED OF STRANDS OF COPPER-CONTAINING ALLOY WIRES CARRYING A FILM CONTAINING 2-MERCAPTOBENZOTHIAZOLE AND 2-AMINOETHANOL. 